Abstract: A slurry spray machine for spraying a settable slurry includes a main passageway configured for receiving a supply of pressurized slurry and having a supply end and an outlet end opposite the supply end. A first compressed gas inlet is disposed intermediate the supply and outlet ends and in fluid communication with the passageway for introducing a first supply of pressurized gas into the slurry, and a second pressurized gas inlet is disposed closer to the outlet end than the first inlet and in fluid communication with the passageway for introducing a second supply of pressurized gas into the slurry. A pressurized supply of adjuvant is provided in fluid communication with the second pressurized gas inlet for providing a blended gas to the second gas inlet. At least one valve is provided for controlling the flow of slurry through the passageway and the flow of the first and second gases into the passageway.

Abstract: A high strength, low density fiber board panel for use in the furniture industry is provided, including mineral wool, a lightweight aggregate material, cellulosic fiber, a binding agent and gypsum. The mineral wool makes up approximately 0% to 33%, the lightweight aggregate material approximately 25% to 41%, the cellulosic fiber approximately 20% to 35%, the binding agent approximately 5% to 9%, and the gypsum approximately 0% to 23%, of the dry solids weight of the panel.

Abstract: A non-combustible gypsum/fiber board comprises two surface layers and at least one core layer, wherein the surface layers comprise a gypsum composition that is reinforced with organic fibers, and the core layer comprises a gypsum composition containing no more than about 3% by weight of organic materials.

Abstract: A direct mount ceiling grid system comprising a plurality of base grid members, cross grid members, and channel grid members for mounting ceiling panels close to a mounting surface. The base grid members are elongated T-shaped beams having a base flange and a transversely extending web having a thicker bulb portion at its marginal end. The base flange of each base grid member is directly mounted to a mounting surface. The channel grid members are elongated beams having two parallel transversely extending webs forming a channel therebetween. Upon installation of ceiling panels, the channel of the channel grid members removably engage the bulb portion of the transversely extending web of the base grid members. The channels have hook portions of the parallel webs of the channel grid members and deflect to allow capture of the bulb portion. The base flange of the base grid members and the base flange of the channel grid members capture the ceiling panels placed therebetween.

Abstract: An improved method for texturing gypsum fiber panels and producing surface textured panels, edge tapers, and deeper patterned wainscot-type panels, involving the use of a flexible die with a textured surface. The die is pressed onto the panel in its slurry state just after the onset of an exothermic rehydration reaction. Partial hydration and setting occur during pressing by the die to form a textured mat. The mat is removed from contact with the die at a point along the rehydration temperature curve about at or less than one-half of the rise to the greatest rehydration temperature.

Abstract: An improved water resistant gypsum board is made by adding an aqueous wax emulsion containing a cationic surfactant to an aqueous slurry containing calcium sulfate and host particles at a slurry temperature which maintains calcium sulfate hemihydrate crystals. The wax emulsion is stable at the temperature of slurry which maintains the calcium sulfate hemihydrate. The slurry is then dewatered and rehydrated to form a gypsum board and dried at a temperature to melt the wax.

Abstract: A composition suitable for making acoustical tiles in a water-felting process comprises expanded perlite, cellulosic fiber, and, optionally, a secondary binder and mineral wool. The perlite has been treated to reduce its water retention.

Abstract: A composition suitable for making acoustical tiles in a water-felting process comprises expanded perlite, clay, a binder component selected from the group consisting of starch, latex, cellulosic fiber and mixtures thereof and optionally mineral wool. The use of an expanded perlite having a relatively high density, preferably between about 9 pounds per cubic foot to about 20 pounds per cubic foot, enables the formation of a suitable slurry with a relatively low amount of water and enables a more complete dewatering of the mat prior to drying.

Abstract: A process is described for making a gypsum board having improved water resistance. The resulting gypsum board products are also described. The process comprises adding an aqueous siloxane emulsion to an aqueous slurry of a calcium sulfate material and host particles, where the siloxane emulsion is stable under the condition in which the slurry is maintained. The process further includes passing said siloxane containing slurry onto a flat porous forming surface to form a filter cake; removing a substantial portion of the water from the filter cake through the porous surface; pressing the filter cake to form a board and remove additional water; and drying the board to remove the remaining free water and to cause the core of the board to reach a temperature sufficient to cure the siloxane.

Abstract: A cementitious composition of the setting type which can be kept in a ready-mixed state and which can be caused to set and harden upon introduction of an accelerator with reproducibility and set time predictability. The cementitious base composition contains calcium sulfate hemihydrate as a principal filler material and certain non-calcium bearing phosphate additives which prevent setting action in the presence of water. An accelerator, such as zinc sulfate, may be added to the ready-mixed, cementitious composition to initiate the setting action, or the ready-mixed cementitious composition can be used as a drying type joint compound without the addition of an accelerator.

Abstract: The invention provides an improved method for preparing foamed gypsum products. The invention can utilize a single mixing chamber and significantly improve the efficiency of foaming agent usage. In the method of the invention the point of insertion of aqueous foam into calcined gypsum slurry is positioned such that the foam is agitated less than the calcined gypsum to thereby minimize destruction of the foam while still uniformly dispersing the foam in the calcined gypsum slurry. This is accomplished, for example, by locating an inlet for foam closer to the discharge outlet of a slurry mixing chamber than the location of the inlet for calcined gypsum or by locating the foam inlet in a discharge conduit connected to the discharge outlet of the slurry mixing chamber.

Abstract: This invention is a process and foaming system for producing foamed gypsum board which permits the production and control of large foam voids in the gypsum core by adjusting the ratio of a first foaming agent and a second foaming agent. My process includes the steps of preforming a first foaming agent which forms stable foam voids in a gypsum slurry and independently preforming a second foaming agent which forms unstable foam voids in a gypsum slurry. Independently, blending the two different foaming agents is the key to controlling void size. A greater amount of the second foaming agent and a lesser amount of the first foaming agent is preferred.

Abstract: An apparatus for producing a fissured, acoustical ceiling panel wherein the pins used to fissure the panel are roll applied thereto. The pins are embedded in flexible, resilient polymeric plates, and a plurality of the plates are attached to a rotary drum which is used to apply the fissuring pins to the surface of the panel. The invention also includes the method for manufacturing the polymeric plates which are molded and formed with the fissuring pins embedded therein.

Abstract: An acoustical tile composition based on a gypsum/cellulosic fiber composition which can replace all or a portion of the mineral wool normally present in acoustical ceiling tiles. The gypsum/cellulosic fiber composition is combined with a lightweight aggregate material and a binder to form a composition which is used in a water-felting process to manufacture acoustical ceiling tiles and panels. The preferred source of the cellulosic fiber is a composite gypsum/cellulose fiber material which is prepared by mixing the gypsum and cellulosic fiber material with sufficient water to form a dilute slurry which is then heated under pressure to calcine the gypsum, converting it to an alpha calcium sulfate hemihydrate. The resulting composite material comprises cellulosic fibers physically interlocked with calcium sulfate crystals. Another source of both gypsum and cellulosic fibers is waste (scrap) gypsum wallboard. Expanded perlite is the preferred lightweight aggregate material.

Abstract: This invention is a polymer modified, high density gypsum composition that is useful as a machinable plaster. For example, the machinable plaster can be used with computer aided carving machines for modeling in the automobile industry. The polymer is a redispersable polymer such as ethylene/vinyl acetate/vinyl chloride polymer.

Abstract: An improved reusable multiactive electrophotographic element has a charge-transport layer comprising a triarylamine charge-transport material in a binder comprising a polyester containing recurring units having the structure ##STR1##